Hydraulically actuated control systems are commonly used in many industries to control large mechanical equipment, and in one particular instance, are used to control power generation machines, such as turbines. Known hydraulically actuated control systems used in the power generation industry may, for example, include a hydraulically actuated trip control system or other protection system configured to stop the turbine (i.e., trip the turbine) upon the detection of an abnormal operating condition or other system malfunction. Typically, these hydraulically actuated control systems include a hydraulic manifold which has numerous different types of hydraulic lines or channels disposed therein, including a main pressure channel (which supplies pressured fluid from a high pressure fluid source), a tank channel (which returns hydraulic fluid to a reservoir or tank at low pressure), and one or more control channels which are used to control the operation of various different equipment, such as shut-off valves, etc. Generally speaking, various different control valves, such as electrically actuated control or solenoid valves, are mounted onto the control manifold at appropriate places to control the pressure and flow of hydraulic fluid within the various control lines of the manifold based on commands sent from a separately programmed controller. Such a hydraulically actuated control system for use in performing hydraulically actuated shut-downs within a steam operated turbine is disclosed in U.S. Patent Application Publication No. 2006/0230755-A1. However, many other and different types of hydraulic control systems are used to perform many different functions and operations in many different industries.
As will be understood, there can be many different numbers of and types of valves and other components attached to a hydraulic manifold used in a hydraulically actuated control system to perform various different functions with respect to controlling and delivering hydraulic fluid to various other devices within the plant or control system. While using these configurations is generally not a problem, it can sometimes be difficult to service known hydraulically actuated control systems, especially when such systems have a large number of valves or other components attached to a hydraulic manifold. In particular, to remove or replace a valve or other component attached to a hydraulic manifold of a hydraulically actuated control system, it is generally necessary to block the pressure lines going into the valve (to prevent the release of pressurized hydraulic fluid from the manifold during removal of the valve) and to then bleed the valve lines to remove existing high pressure conditions within the channels or ports of the valve. Only after blocking and bleeding the valve or other component, is it safe to begin to remove the valve or other component from the hydraulic manifold as removal of a valve or other component having highly pressurized fluid therein, or while this component is exposed to an unblocked high pressure line of the hydraulic manifold, can result in highly pressurized fluid squirting out of the valve or manifold during the removal process, which can result in high velocity fluid penetrating or cutting into objects or exposed skin, and can even cause the valve itself to be ejected away from the manifold at a high velocity. Both of these conditions result in serious safety hazards to personnel as well as a potential cause of damage to the control system hardware.
Thus, it is necessary, when servicing known hydraulic control systems, to first block and bleed a valve or other component to be serviced, prior to removing this component from the system. In many control systems, these blocking and bleeding operations may require halting the operation of the entire control system to remove pressure from the appropriate pressure channels going into or coming out of the valve to be serviced. In many instances, it is extremely undesirable and sometimes very expensive to halt the operation of the control system each time there is a need to perform service on some component of the system.
Some hydraulically actuated control systems are designed with specific components that enable a technician to block and bleed specific valves attached to the hydraulic manifold without shutting the control system down, i.e., to perform these operations while the manifold operates normally to provide fluid to other components of the system. However, in these control systems, it is necessary for the technician to manually initiate and implement separate block and bleed operations prior to removing the valve or other component to be serviced. In many cases, these block and bleed procedures are hard to implement or may be complex to perform, resulting in the possibility that the technician incorrectly performs these procedures. Thus, in many cases, the technician may fail to properly isolate the component being removed from the hydraulic manifold because of these difficulties. In other cases, the technician may simply forget to run the appropriate block and bleed procedures, or may think that he or she has run the appropriate procedures when they have, in fact, not done so. Still further, in these systems, it is difficult to tell, by looking at the outside of the hydraulic manifold, if the valve or other component to be serviced has been properly isolated from the manifold, and thus there is no easy way to determine if the appropriate block and bleed procedures have been performed for the component being removed or if, instead, the component is still exposed to a high pressure fluid line. Moreover, these systems require separately controllable valves (or other components) which are used to perform the blocking and bleeding operations on the components being serviced, which results in a large, complex design having separate parts that may be expensive to manufacture and hard to implement.